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worm top ?
Posted: 02:14 pm Nov 25 2011
by l2f
Hello,
I am wondering how to detect a worm top, I'm reading (
http://justkdx.dirtrider.net/printcarbtuning.html) about jetting the carb of my 2002 kdx220
Thank you in advance for your help
l2f
Posted: 03:55 pm Nov 25 2011
by chkdx
What is a worm top?
Posted: 10:34 pm Nov 25 2011
by Julien D
I"m guessin you mean worn top end?
Compression test would be a good place to start. Even better, if it's a used 2 stroke you picked up, go ahead and throw a new top end in it. since you ride a 220 you need to be sure there's a forged piston in there. The stock pistons are not reliable int he 220's, and if they drop a skirt, could cost you a bundle.
Posted: 04:56 am Nov 26 2011
by factoryX
What would be average compression? Mine is currently at 140lbs
Posted: 09:26 am Nov 26 2011
by Julien D
They did change the usuable compression spec a couple times. I'm not 100% sure off-hand what it is for an H bike, but my 89 manual says something rediculously like 90 - 180 usable range. AFter break in on the last top end my gauge showed 160.
(btw, i'm moving this to general Q/A as it does not relate to RB mods at all)
Posted: 04:22 pm Nov 26 2011
by OLHILLBILLY
H model (200 anyway) usable compression range is given as 95-151psi.
Posted: 09:27 am Nov 28 2011
by l2f
juliend wrote:I"m guessin you mean worn top end?
Compression test would be a good place to start. Even better, if it's a used 2 stroke you picked up, go ahead and throw a new top end in it. since you ride a 220 you need to be sure there's a forged piston in there. The stock pistons are not reliable int he 220's, and if they drop a skirt, could cost you a bundle.
The previous owner did it, he put a wisco.
Thanks
Posted: 09:32 am Nov 28 2011
by l2f
juliend wrote:I"m guessin you mean worn top end?
Compression test would be a good place to start. Even better, if it's a used 2 stroke you picked up, go ahead and throw a new top end in it.
I will double check the compression and see with the manual. My 220 is a used one but it runs good. In the "how to jetting", before doing the jetting session you have to check the worm top end and the gas carburation level that why I ask this question.
Thanks
Posted: 09:52 am Nov 28 2011
by fuzzy
The previous owner did it, he put a wisco.
That's great. I'd just start jetting it. Unless damage is done due to running lean/etc the top ends on these last A LONG time.
Posted: 10:22 am Dec 05 2011
by l2f
fuzzy wrote:The previous owner did it, he put a wisco.
That's great. I'd just start jetting it. Unless damage is done due to running lean/etc the top ends on these last A LONG time.
Happy to hear that
thank you